Local costs · East of England · September 2026
How much does an extension cost in Colchester?
A mid-range 25 m² single-storey extension in Colchester costs about £68,000 to £83,500 including VAT, or £2,700 to £3,300 per m² at East of England prices. Colchester’s own published charge for building control on a 10 to 40 m² extension is £925 (full plans, VAT status not stated): 10% above the typical council (£840). With a measured survey, building regulations drawings, a structural engineer, Colchester’s own building control charge and a 15% contingency, plan for £83,000 to £105,000.
Work out your project in Colchester
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Typical prices in Colchester
| Project | Building work | Budget to plan for |
|---|---|---|
| Single-storey extension, 25 m² | £68,000 to £83,500 | £83,000 to £105,000 |
| Double-storey extension, 40 m² | £97,500 to £123,000 | £118,000 to £152,000 |
| Dormer loft conversion, 30 m² | £50,500 to £62,000 | £62,000 to £80,000 |
| Kitchen, medium | £9,300 to £16,600 | £10,700 to £19,000 |
| Bathroom refit | £6,300 to £9,400 | £7,200 to £10,800 |
Building prices in the East of England run about 7% above the UK average outside London. Kitchens and bathrooms vary less from place to place than extensions and lofts.
Building control fees in Colchester
| Work | Charge |
|---|---|
| Extension up to 10 m² (full plans) | £565 |
| Extension 10 to 40 m² (full plans) | £925 |
| Larger extension, 40 to 100 m² (full plans) | £1,155 |
| Extension 10 to 40 m² (building notice) | £925 |
| Loft conversion up to 40 m² | £1,075 |
| Garage conversion | £650 |
Colchester’s own published charge for building control on a 10 to 40 m² extension is £925 (full plans, VAT status not stated): 10% above the typical council (£840). Source: Colchester’s building control charges. The schedule doesn’t give a start date (page indexed as “New Building Regulation application charges from 1 April 2026”). The inspection and building notice charges include VAT; the schedule doesn’t say whether its plan check fee does.
Check before relying on it: the schedule doesn’t say whether VAT is included.
Private building control firms (registered building control approvers) set their own prices and are often competitive, so it is worth asking one or two for a quote as well. See how Colchester compares with every council we checked.
Notes on Colchester’s schedule
Colchester publishes its charges on its own page. A full plans charge is a plan check fee of £275 plus the inspection charges, which comes to the same as its building notice charge.
Planning
If your extension needs planning permission, a householder application in England costs £548. Many single-storey rear extensions are permitted development and need no application, and a lawful development certificate (£274) confirms it in writing.
Other councils in the East of England
Building control for a 10 to 40 m² extension:
- Peterborough: £666
- Uttlesford: £786
- Bedford: £915.79
- North Norfolk: £919.20
- Maldon: £946.80
- Watford: £1,065
- St Albans: £1,065
Questions people ask
How much does an extension cost in Colchester?
A mid-range 25 m² single-storey extension in Colchester costs about £68,000 to £83,500 including VAT for the building work, or £2,700 to £3,300 per m², based on East of England prices reviewed in September 2026. With a measured survey, design, a structural engineer, Colchester’s own building control charge and a 15% contingency, plan for £83,000 to £105,000.
How much is building control in Colchester?
Colchester’s own published charge for full plans approval of a 10 to 40 m² extension is £925 (VAT status not stated). The schedule doesn’t give a start date (page indexed as “New Building Regulation application charges from 1 April 2026”).
How much does a loft conversion cost in Colchester?
A mid-range 30 m² dormer loft conversion in Colchester costs about £50,500 to £62,000 including VAT for the building work, and about £62,000 to £80,000 with fees, Colchester’s own building control charge and a 15% contingency.
Before you get quotes
- How to compare builders’ quotes line by line
- Plan your whole budget, including the costs people forget
- When quotes arrive, check each one against the typical range for your area
Work in Colchester? Firm listings on Estiquote’s map of checked local firms open soon: see what you’ll need. Listing will be free while we build the map, with at least 30 days’ notice before any charge.